html, body {
    height: 100%;
}

body {
    margin: 0;
    padding: 0;
    font-family: "Microsoft YaHei";
    font-size: 14px;
    line-height: 18px;
    letter-spacing: 2px;
}

#topics {
    width: 77%;
    margin: 0 auto
}

.button-wrap {
    margin: 30px;
}

.button-wrap a:hover {
    font-size: 40px;
    font-weight: bolder;
    text-decoration: none;
}